Problem of the Week: Due Thursday September 16

On July 5, in the area around Center Village, there was great excitement.  Six people had reported to the police that they had seen Big Foot, a large, hairy creature sometimes seen, but never captured.  The next day, twice as many people had called the police, sure they has seen the creature.  Each day the police received twice as many calls as the day before.  After a total of more than 300 calls, the police took the phone off the hook.  On what day did the police take the phone off the hook?